1. Technical Field
The present disclosure relates to a photosensitized photoelectric conversion element. The term “photosensitized photoelectric conversion element” encompasses what is called dye-sensitized solar cells and also encompasses photoelectrochemical power generation elements that can generate power even in environments having a relatively low illuminance, such as indoors.
2. Description of the Related Art
In recent years, dye-sensitized solar cells employing dyes as photosensitizers have been developed. A typical dye-sensitized solar cell includes a photoanode containing a dye, a counter electrode, and an electrolyte medium disposed between the photoanode and the counter electrode. The electrolyte medium is, for example, an electrolyte solution containing an oxidation-reduction substance. The oxidation-reduction substance is called mediator.
Enhancement of characteristics of dye-sensitized solar cells requires enhancement of characteristics of components of the solar cells. For example, Japanese Unexamined Patent Application Publication No. 2008-204785 states that use of a dye molecule having a fluorene residue having a specific rigid planar structure can increase photoelectric conversion efficiency (hereafter simply referred to as “conversion efficiency”). International Publication No. 2011/118197 states that use of, as mediators, radical compounds having an average molecular weight of 200 or more and including 4-acetamide-2,2,6,6-tetramethylpiperidine-1-oxyl can increase conversion efficiency.